Bravo! I am running a Z390 MOBO as well, along with an RX580 (I assume you meant RX, not MX?). My processor is an i5 but otherwise it's pretty much the same system. Would I be able to get your settings for Opencore by chance? I tried it following the install (I'm not too knowledgable so I went real slow!) and it took like 2 hours for me to download and get everything straight and it didn't work. I'd love to try with yours if you'd be so willing!OpenCore - updated through Apple Menu - System Preferences -> Software Update. No issues, updated just like on a real Mac.
thank you manmacOS Catalina 10.15.7 Supplemental Update 19H15.